Applied Mechanics and Materials Vol. 251

Abstract: This paper makes an experimental research on the screw conveyor feeding system in biomass pyrolytic devices. And ensure the screw conveyor’s boot order, appropriate speed and part of the power consumption. In the end, it makes a comparison with the experimental result and the theoretical calculation result. And find out the error, make an useful suggestion to the further optimization of biomass pyrolytic devices as well.

Abstract: Two methods are proposed in the paper to reduce the flow and pressure pulsation caused by the reciprocating pump in aircraft deicing system. First, the control algorithm for multiple phases of pumps is used to cut down the pulse energy among the pumps. Then the inflatable accumulator is used in combination with pumps to make the fluid more stable. At last, the simulation results show that the methods can effectively decrease the pulsation in the system.

Abstract: Various methods of calculating transmission error in spur and helical gears are used to predict T.E. at the design stage. In order to reduce the driveline noise of the noise excitation mechanism, an advanced algorithm is used to predict and optimize the TE of a gear pair and the system response of specified TE excitation is investigated for the driven tool holder. And the CAD model was then meshed in Hypermesh with designable and non-designable areas. A pair of spur gears were investigated through static and dynamic analysis in detail.

Abstract: Limited memory resource has always been deemed as the major bottleneck of the program performance, not excepting for dynamic binary translation (DBT) [1] system. However, traditional methods seldom enable this issue mentioned to be solved better due to a fix cache size routinely assigned for codes without considering the program behavior on the fly. Though some prediction methods implemented via LRU [2] histograms can achieve better performance in Operating System, unlike pages in memory, blocks in DBT have unfixed sizes each other, making the prediction imprecise. In this paper, we present a new replace policy named DCC (Dynamic Code Cache) based on working set [3] for bounded code cache, which would dynamically change the size of the code cache and clear the cache according to the information of working set detected. It would sacrifice a small part of the performance to save the space, especially when many great or complicated applications are running on the same physical machine, and the performance might be better under this condition. For Evaluating, we test this strategy on a DBT system named Crossbit [4].We get around 30% space saved up with about 12% running time sacrificed.

Abstract: In achieving the practical use of vibration power generation, the challenges are that the energy to be generated is small and the vibration frequency range for efficient power generation is limited. So, it is needed to improve the output level and establish a vibration transmission structure capable of covering a wider vibration frequency range. In this report, we propose a multi-axis vibration power generation device that is mounted on the vehicle and capable of generating electric power from vibrations in the running vehicle and evaluate its principle model based on the stress analysis. For the model, we employed the structure in which the elastic body (a flat spring with piezoelectric elements on it) is deflected by mass vibration and the elements are bent and strained. We made two types of the principle models using the same elastic body; one is H-type having a mass on both sides of the elastic body, and the other is T-type having a mass on one side only, and conducted tests for the system identification of them.

Abstract: This paper presents a novel vibration power generation device for vehicles where effective power generation can be obtained by multi-mode vibration of the vehicles. First, road tests of the vehicle are performed, and then the obtained data is analyzed. Next, a vibration power generation device specially designed for the vehicle is proposed. This new device is composed of the multiple masses and spring plates equipped with lead zirconate titanate (PZT), and is effective in multi-mode vibration. The validity of the developed device is confirmed by the simulation and experimental results.

Abstract: This paper presents the development of the 3-axis vibrating machine precisely reproducing vehicle's acceleration characterized with multi-mode vibration. For the reproduction in vertical axis, at first, the system identification experiment of the vibrator is carried out. Using the identified model, the feedforward control based on the pole-zero cancellation method is applied to realize the ideal transfer gain of one from the acceleration reference to its output. Next, for reproducing the acceleration in horizontal plane, the continuous-path tracking (CPT) control system is constructed using the precision XY stage. In the CPT control system, the disturbance observer is introduced focusing on the accurate reproduction within limited frequency. Finally, the experimental verification of the proposed 3-axis acceleration vibration reproduction system is shown using the developed DSP-controlled 3-axis vibrating machine.

Abstract: Auxiliary brake sets had been widely used for heavy duty trucks and advanced buses. They played a role of split-flow braking load of main brake system. As one of auxiliary brake sets eddy current retarder had good braking performance and braking stability, and it is automotive and maintain constant speed by its continual braking. In this paper, key technologies of eddy current retarder, such as braking torque, working volt and current, magnetic circuit, material of rotor plate and iron, heat dissipation performance of rotor plate, match between eddy current retarded and automobile, and effect of temperature rise on its braking performance were presented and discussed in detail. Meanwhile, advantage and disadvantage of eddy current retarder were analyzed.

Abstract: To meet the demand for low insertion loss, we have studied a SAW filter with single phase unidirectional transducer (SPUDT) structure using piezoelectric materials YZ-LiNbO₃. This article shows the simulation results of the SAW filter using Matlab software with the SAW velocity 3488m/s and electromechanical coupling constant 0.048. The theoretical center frequency is 72MHz and the 3dB bandwidth is 2.9MHz. The total frequency response of the entire SAW device is the product of the frequency response of the input transducer and the output transducer. It can be seen from the simulation results that the magnitude response and the linear phase response of interdigital transducer are consistent with the theoretical values and the minimum insertion loss reaches 5.43dB. So the low insertion loss SAW filter with SPUDT structure using YZ-LiNbO₃ adapts the requirements of the radar, communications and other electronic systems.

Abstract: In mechanical processing, according to the requirements of components’ high surface quality, this paper makes a structure design of high-speed cylindrical grinding machine transmission system. Such structure is mainly used in high-speed grinding and powerful grinding, so as to improve the grinding efficiency. The design provides a certain basis for the further research of grinding machine structure.